/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.type.descriptor.java;

import java.io.Reader;
import java.io.Serializable;
import java.sql.NClob;
import java.sql.SQLException;
import java.util.Comparator;

import org.hibernate.HibernateException;
import org.hibernate.engine.jdbc.CharacterStream;
import org.hibernate.engine.jdbc.NClobImplementer;
import org.hibernate.engine.jdbc.NClobProxy;
import org.hibernate.engine.jdbc.WrappedNClob;
import org.hibernate.engine.jdbc.internal.CharacterStreamImpl;
import org.hibernate.type.descriptor.WrapperOptions;

Descriptor for NClob handling. 
 Note, nclobs really are mutable (their internal state can in fact be mutated). We simply treat them as immutable because we cannot properly check them for changes nor deep copy them. 
Author:
Steve Ebersole/**
 * Descriptor for {@link java.sql.NClob} handling.
 * <p/>
 * Note, {@link java.sql.NClob nclobs} really are mutable (their internal state can in fact be mutated).  We simply
 * treat them as immutable because we cannot properly check them for changes nor deep copy them.
 *
 * @author Steve Ebersole
 */
public class NClobTypeDescriptor extends AbstractTypeDescriptor<NClob> {
	public static final NClobTypeDescriptor INSTANCE = new NClobTypeDescriptor();

	public static class NClobMutabilityPlan implements MutabilityPlan<NClob> {
		public static final NClobMutabilityPlan INSTANCE = new NClobMutabilityPlan();

		public boolean isMutable() {
			return false;
		}

		public NClob deepCopy(NClob value) {
			return value;
		}

		public Serializable disassemble(NClob value) {
			throw new UnsupportedOperationException( "Clobs are not cacheable" );
		}

		public NClob assemble(Serializable cached) {
			throw new UnsupportedOperationException( "Clobs are not cacheable" );
		}
	}

	public NClobTypeDescriptor() {
		super( NClob.class, NClobMutabilityPlan.INSTANCE );
	}

	@Override
	public String extractLoggableRepresentation(NClob value) {
		return value == null ? "null" : "{nclob}";
	}

	public String toString(NClob value) {
		return DataHelper.extractString( value );
	}

	public NClob fromString(String string) {
		return NClobProxy.generateProxy( string );
	}

	@Override
	@SuppressWarnings({ "unchecked" })
	public Comparator<NClob> getComparator() {
		return IncomparableComparator.INSTANCE;
	}

	@Override
	public int extractHashCode(NClob value) {
		return System.identityHashCode( value );
	}

	@Override
	public boolean areEqual(NClob one, NClob another) {
		return one == another;
	}

	@SuppressWarnings({ "unchecked" })
	public <X> X unwrap(final NClob value, Class<X> type, WrapperOptions options) {
		if ( value == null ) {
			return null;
		}

		try {
			if ( CharacterStream.class.isAssignableFrom( type ) ) {
				if ( NClobImplementer.class.isInstance( value ) ) {
					// if the incoming NClob is a wrapper, just pass along its BinaryStream
					return (X) ( (NClobImplementer) value ).getUnderlyingStream();
				}
				else {
					// otherwise we need to build a BinaryStream...
					return (X) new CharacterStreamImpl( DataHelper.extractString( value.getCharacterStream() ) );
				}
			}
			else if (NClob.class.isAssignableFrom( type )) {
				final NClob nclob =  WrappedNClob.class.isInstance( value )
						? ( (WrappedNClob) value ).getWrappedNClob()
						: value;
				return (X) nclob;
			}
		}
		catch ( SQLException e ) {
			throw new HibernateException( "Unable to access nclob stream", e );
		}
		
		throw unknownUnwrap( type );
	}

	public <X> NClob wrap(X value, WrapperOptions options) {
		if ( value == null ) {
			return null;
		}

		// Support multiple return types from
		// org.hibernate.type.descriptor.sql.ClobTypeDescriptor
		if ( NClob.class.isAssignableFrom( value.getClass() ) ) {
			return options.getLobCreator().wrap( (NClob) value );
		}
		else if ( Reader.class.isAssignableFrom( value.getClass() ) ) {
			Reader reader = (Reader) value;
			return options.getLobCreator().createNClob( DataHelper.extractString( reader ) );
		}

		throw unknownWrap( value.getClass() );
	}
}